SUBJECT: # 27402: Alumacraft 1650 Tunnel Hull
Kevin Broussard (18.104.22.168) from LOUISIANA on 8/15/05 11:18:00 PM
I recently bought a 16ft. Alumacraft Tunnel w/ a 40hp Merc. tiller, 13P 4 blade Power Tech. This is my first tunnel. The problem I'm having is cavatation, in forward, in reverse, when I'm slow turning, fast turning it's driving me insane. Oh yeah, and over reven. I was hoping to just get in the boat and hit those hard to get to fishng spots but, right now I can't even leave the damn landing.................... Well, fellas where do I start.
- 8/15/05 11:37:00 PM
TxDude (22.214.171.124) from TEXAS says slipping and sliding...
Sounds like you need to get the prop down in the water more. Common thing with tunnels and highly jacked up motors, you lose the water flow during the turns. So move it down so there is more prop just below the bottom of the hull. Good luck.
- 8/16/05 9:53:00 AM
Roby (126.96.36.199) from TEXAS says hyd. jack plate
Kevin, the most useful thing you can do for your rig is install a hyd. jack plate. You can fine tune the depth of the engine to get maximum performance from your sled. This may not be feasabe with tiller steering though. It sounds like your engine is mounted too high. If possible, drop the engine a bolt hole at a time to get it to stop cavitating. Your engine must be mounted way high. My experience with aluminum tunnel hulls is with a 90 horse on a 18 foot boat with a 4 blade prop. We could run the jack plate at full 6" lift and take off from a dead stop with no problems. You should be able to raise that engine and get overheating problems long before the prop starts to cavitate. You should be able to run that engine with the cavation plate a couple of inches above the top of the tunnel. It may be that 40 horses is not enough power to push the boat fast enough to get the tunnel working properly. One last comment. Tunnel boats perform very poorly in reverse. I have never been on any tunnel boat that will back up like a standard hull.
- 8/24/05 4:46:00 PM
Russ C (188.8.131.52) from ALABAMA says Tunnel Hull
I added a Bob's Stabilizer Plate to my Scout 177 tunnel hull & it solved the problem of blowing out the prop in sharp turns by holding water to the prop.